<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="./lib/react.js"></script>
    <script src="./lib/react-dom.js"></script>
    <script src="./lib/browser.js"></script>
</head>
<body>
    <div id="root"></div>

    <script type="text/babel">

        
    class App extends React.Component{

        constructor(props){
            super(props)

            this.state ={
                loading:true
          }
        }

        componentDidMount(){
            setTimeout(() =>{
                this.setState({
                    loading:false
                })
            },3000)
        }

        render(){
            if(this.state.loading){
                return<h1>正在加载。。。。。</h1>
            }else{
                return(
                    <div>
                    <h2>数据加载</h2>
                </div>
                )
               
            }
        }
    }

        ReactDOM.render(<App/>,document.getElementById("root"))
    
    
    </script>
</body>
</html>